In a conventional remote control transmitter that remotely controls the operation of a home appliance, such as a television or an air conditioner, by emitting an optical control signal thereto, the entire case of the transmitter is made in a long and thin shape, and a light emitting device, which emits the optical control signal, is housed in the tip part of the case in the longitudinal direction so that an operator can control the transmission direction of the optical control signal.
The light emitting device that is housed inside the case is covered by a transparent protective filter, which is disposed on and provided to a tip surface of the case so that the light emitting device is not damaged by the operator's finger or by the accidental application of some external force. However, if one attempts to reduce the size of the remote control transmitter to an extent such that it can be grasped with one hand, there then is a risk that the finger of the operator who grasps the case will cover the transparent protective filter and thereby block the optical control signal. Therefore, the conventional remote control transmitter is designed so that the width of the case in the latitudinal direction is of such an extent that it can be grasped with one hand, and the width in the longitudinal direction is of an extent such that the fingers that grasp the case do not reach the tip surface. Such a configuration is disclosed by Japanese Published Unexamined Patent Application No. 2005-252336, which is hereby incorporated by reference in its entirety herein.
A conventional remote control transmitter 100 of this type is illustrated in FIG. 7 and FIG. 8. A case 101, which has a rectangular contour, is formed hollowly by superposing an upper case 101a and a lower case 101b, which are made of synthetic resin. A printed wiring board 102 is supported inside the hollow case 101, and an infrared light emitting device 103, which emits an infrared control signal that comprises infrared rays, is mounted to a front end (upper end in FIG. 8) of the printed wiring board 102.
Additionally, a plurality of key switches 104 as well as circuit elements, such as a control device 105 that generates a prescribed control command in accordance with a key switch 104 on which an input operation has been performed, are mounted to the printed wiring board 102, and batteries 106, which constitute the drive power source of these circuit elements, are housed in a gap that is between the rear end (the lower end in FIG. 8) of the printed wiring board 102 and the case 101.
The infrared light emitting device 103, which is housed in the front end part of the case 101, emits and outputs an infrared control signal frontwards, and a transparent protective filter 107 is attached to a front surface of the case 101 that intersects the optical path of that infrared control signal. The transparent protective filter 107 transmits the infrared control signal, prevents the infiltration of dust into the case 101, and protects the infrared light emitting device 103, which is housed inside the case 101, from unexpected external forces.
A liquid crystal display panel 108, which displays the results and the like of input operations that are performed on the key switches 104, is mounted to the remote control transmitter 100 between the key switches 104 and the infrared light emitting device 103 of the printed wiring board 102. A transparent protective panel 109 is attached to the face side of the liquid crystal display panel 108 in an area of the upper case 101a, and thereby the operator views the display of the liquid crystal display panel 108 through the transparent protective panel 109 while performing a prescribed input operation.
When the operator orients the front end of the remote control transmitter 100 toward a controlled apparatus and performs an input operation on any one of the key switches 104, the control device 105 generates a control command that is in accordance with the key switch 104 on which the input operation was performed, and controls the infrared light emitting device 103 so that it flashes based on the control signal, which is modulated with the control command. Thereby, the infrared light emitting device 103 emits and outputs an infrared control signal that includes the control command to the controlled apparatus through the transparent protective filter 107, and the controlled apparatus demodulates the control command from the infrared control signal and executes an operation that is in accordance with the control command. Furthermore, under the control of the control device 105 the liquid crystal display panel 108 displays information about the control command during this time through the transparent protective panel 109.
With the conventional remote control transmitter 100 discussed above, the infrared light emitting device 103 that emits and outputs the infrared control signal frontwards is housed in the front end part of the case 101, and numerous key switches 104, on which input operations are performed, are disposed and provided to the rear of the case 101. Therefore, the operator naturally grasps the rear of the case 101, and the operator's finger does not cover the transparent protective filter 107, which is disposed and provided to the front surface of the case 101, and the infrared control signal is not blocked accidentally.
Nevertheless, because the case 101 is made so that it is longer than the length of the hand that grips it and with a structure wherein the light emitting device is provided at its front end part, the overall size of the case 101 is large. In order to dispose the light emitting device 103 at a position that is to the front of the case 101 so that it is spaced apart from the part that is grasped by the operator, it is necessary to extend the printed wiring board 102 frontward to the position at which the light emitting device 103 is disposed, and to support, supply power to, and wire the light emitting device 103. Furthermore, all of these elements must be covered and protected an extended case 101.
As a result, it becomes difficult to reduce the weight of the entire remote control transmitter 100 and, as the case 101 is extended frontward of the position at which it is grasped, the case 101 becomes difficult to grasp with one hand and the key switches 104 become difficult to operate with one hand.
Furthermore, the external form of the case 101, which must be made long and thin, governs the exterior design of the entire remote control transmitter 100, and it is therefore not possible to obtain a remote control transmitter of a novel design that sparks consumer interest.
In addition, with a remote control transmitter that comprises the liquid crystal display panel 108 and displays supplemental information about the input operation, as in the conventional remote control transmitter 100 discussed above, installation space is needed so that the liquid crystal display panel 108 can be attached inside the case 101 behind the light emitting device 103, and the case 101 cannot be formed narrowly at the position at which the liquid crystal display panel 108 is attached. Therefore, the case 101 is difficult to grasp with one hand, and there is a risk that the display that is presented by the liquid crystal display panel 108 will be covered by the grasping hand.
Furthermore, with the remote control transmitter 100 that comprises the liquid crystal display panel 108, the light emitting device 103 and the liquid crystal display panel 108 are housed inside the case 101 at different positions, and therefore openings must be provided in the front surface and the face surface of the case 101 for attaching, respectively, the transparent protective filter 107 and transparent protective panel 109, which are prepared separately.